Automated semiconductor immersion processing system

ABSTRACT

A process system for processing semiconductor wafers includes a stocker module, and immersion module, and a process module. A process robot moves on a lateral rail to transfer wavers between the modules. The immersion module is separated from the other modules, to avoid transmission of vibration. Immersion tanks are radially positioned within the immersion module, to provide a compact design. An immersion robot moves batches of wafers on an end effector between the immersion tanks. The end effector may be detachable from the immersion robot, so that the immersion robot can move a second batch of wafers, while the first batch of wafers undergoes an immersion process.

The field of the invention is automated semiconducted wafer processingsystems, used for processing semiconductor wafers, hard disk media,semiconductor substrates, optical media and similar materials requiringvery low levels of contamination.

BACKGROUND OF THE INVENTION

Computers, televisions, telephones and other electronic products containlarge numbers of essential electronic semiconductor devices. To produceelectronic products, hundreds or thousands of semiconductor devices aremanufactured in a very small space, using lithography techniques onsemiconductor substrates, such as on silicon wafers. Due to theextremely small dimensions involved in manufacturing semiconductordevices, contaminants on the semiconductor substrate material, such asparticles of dust, dirt, paint, metal, etc. lead to defects in the endproducts.

To exclude contaminants, semiconductor substrates are processed withinclean rooms. Clean rooms are enclosed areas or rooms within asemiconductor manufacturing facility, designed to keep out contaminants.All air provided to a clean room is typically highly filtered to preventairborne contaminants from entering into or circulating within the cleanroom. Special materials and equipment are needed to maintaincontaminants within the clean room at adequately low levels.Consequently, construction and maintenance of clean rooms can be timeconsuming and costly. As a result, the semiconductor processingequipment installed within a clean room should preferably be compact, sothat large numbers of semiconductor wafers can be processed within asmaller space, thereby reducing space requirements and costs.

In the manufacturer of Semiconductor devices from wafers, or in themanufacture of similar flat substrate devices (such as wafers, diskmedia, optical media, etc., collectively referred to herein as“wafers”), it is often necessary or desirable to clean the wafers aftercertain processing steps. Cleaning is typically performed by rinsing anddrying. Centrifugal rinser dryers have long been used for these types ofcleaning steps. In centrifugal rinser dryers, the wafers are held withina rotor and spun at high speed, while sprayed with rinsing and dryingliquids and/or gases. While centrifugal rinser dryers have beensuccessfully used for many years, contamination of wafers can be evenfurther improved, at least in some applications, by immersion processes.

However, immersion processes have their own engineering challenges.Immersion tanks typically require substantial space, which isdisadvantages in a clean room environment. In addition,cross-contamination between liquids in adjacent tanks, or contaminationof wafers by vapors of the liquids, must be minimized. Immersionprocesses and apparatus must also account for dripping of fluid off ofthe wafers, as they are moved between tanks. The inflow, maintenance,and draining of liquids must also be addressed, along with the handlingof vapors generated from the liquids.

Accordingly, it is an object of the invention to provide an improvedsystem for carrying out immersion processes in the manufacture of wafersand similar devices.

It is also an object of the invention to provide an improved immersionmodule subsystem.

It is a further object of the invention to provide improved immersiontank assemblies.

Other objects and advantages will appear. The invention resides not onlyin the systems described, but also in the subsystems andsub-combinations described and illustrated.

SUMMARY OF THE INVENTION

In a first aspect of the invention, an automated semiconductorprocessing system has an indexer or work in progress stocker module orsection, and immersion module or section, and a processing module orsection. A process robot is moveable between the sections. The immersionmodule is detached from the stocker and process modules, to avoidtransmission of vibration to the immersion tanks in the immersionmodule.

In a second and separate aspect of the invention, immersion tanks withinan immersion module are arranged in an offset radial pattern. As aresult, the immersion module has a compact design requiring less floorspace in a clean room environment.

In a third and separate aspect of the invention, an immersion robot iscentrally positioned between immersion tanks, to facilitate movement ofwafers between tanks reducing travel time and distances between tanks,and resulting in a compact design.

In a fourth and separate aspect of the invention, tank lids andcontrolled air flow help to control vapors generated by fluids in thetanks.

In a fifth and separate aspect of the invention, a quick dump rinse tankis provided for rinsing wafers, and then quickly dumping or removing therinse fluid, providing reduced contamination levels.

Other advantages are described. The invention resides not only in thesystem, but also in the sub-systems and sub-assemblies described.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, wherein the same reference number indicates the sameelement, throughout the several views:

FIG. 1 is a front, left and top perspective view of the presentautomated semiconductor processing system.

FIG. 2 is a front, top and right side perspective view thereof.

FIG. 3 is a plan view of the system shown in FIGS. 1 and 2.

FIG. 4 is a left side view of the immersion module shown in FIGS. 1-3.

FIG. 5 is a front, top and right side perspective view of the immersionmodule shown in FIG. 4.

FIG. 6 is a front, top and right side perspective view of the immersionmodule cabinet or housing.

FIG. 7 is a perspective view thereof with cover panels and surfacesremoved, for clarity of illustration.

FIG. 8 is a similar perspective view of the immersion module withimmersion tanks and immersion robot installed.

FIG. 9 is a section view taken along line 9—9 of FIG. 6.

FIG. 10 is a perspective view of a first immersion tank assembly.

FIG. 11 is a perspective view of a second immersion tank assembly.

FIG. 12 is an exploded perspective view of the tank assembly shown inFIG. 10;

FIG. 13 is an exploded perspective view of the tank assembly show inFIG. 11;

FIG. 14 is a section view taken along line 14—14 of FIG. 10.

DETAILED DESCRIPTION OF THE DRAWINGS

Turning now in detail to the drawings, as shown in FIGS. 1-3, anautomated semiconductor processing system has a stocker module orsection 22, and immersion module or section 24, and a process module orsection 26. The process robot 60 moves along a lateral rail 66 extendingbetween the three modules. The process robot 60 has an end effector 64on an articulated arm 62, so that the process robot 60 can engage, lift,carry, install and remove, batches of wafers, or batches of waferssupported in a tray or carrier, between the modules 22, 24 and 26. Astocker module is described, for example, in U.S. Pat. No. 6,279,724,incorporated herein by reference. A process robot and processed moduleare described, for example, in U.S. Pat. Nos. 5,660,517; 5,784,797, and5,664,337, incorporated herein by reference. A loader 34 is located infront of the stocker module 22, for loading and unloading batches ofwafers into the stocker. The wafers may be contained in a tray, carrier,pod or box.

Referring to FIGS. 1-7, the immersion module 24 is positioned betweenthe stocker module 22 and the process module 26. However, the stockermodule 22 and process module 26 both have moving components. The processmodule 26 typically has centrifugal processors, which spin the wafers athigh speeds during processing. The loader and stocker have motorsdriving various subassemblies and components. This can create vibration,which is disadvantageous during immersion processes. Accordingly, theimmersion module 24 is not attached to either the stocker module 22 orthe process module 26. Rather, the immersion module 24 has its ownhousing 70 which is separate from the stocker housing or enclosure 30,and also separate from the process module enclosure 40.

Referring to FIGS. 4, 5 and 6, the immersion module housing 70 issupported on the floor via leveling legs 72. A housing extension 74having an extension tray 76 extends forwardly from the immersion modulehousing 70. As shown in FIG. 4, the lateral rail 66 extends entirelyover the housing extension 74, so that the process robot 60 can movebetween all three modules. However, the lateral rail 66 is not attachedto any part of the immersion module 24, to further reduce anytransmission of vibration into the immersion module 24. The stockerhousing 30 has a side opening 32, and the process module housing orenclosure 40 has a side opening 42, so that the process robot 60 canmove into the stocker module 22 and the process module 26.

As shown in FIG. 6, a front panel 78 having an opening 79 separates theimmersion module chamber or space 75 from the lateral rail 66.

Turning now to FIGS. 4, 7 and 8, a deck 80 in the immersion modulehousing 70 separates the immersion chamber, above the deck 80, from autility space 77, below the deck 80. The utility space 77 holds fluidtanks, pumps, heaters, filters, and other equipment used in carrying outimmersion processes, as is known in the art.

Tank openings 82 are provided in the deck 80. A robot housing 84 isgenerally positioned between the tank openings 82. A floor panel 86generally defines the foot print of the immersion module 24, and extendsunder the deck 80, as well as the housing extension 74. An extensionframe 90 is attached to the immersion module housing 70 and housingextension 74, to enclose the area above the housing extension 74 and infront of the front panel 78.

Referring to FIGS. 3 and 8, in the embodiment shown, three tankassemblies are provided. A first tank assembly 100 is preferably set upas a chemical process tank, for performing a chemical immersion step,using e.g., an acid, HF, etc. The second tank assembly 102 preferablyprovides a quick dump rinse, for rinsing wafers after a chemicalimmersion step. The third tank assembly 104 preferably provides waferdrying, using known drying techniques . A fourth tank assembly 105,shown in dotted line in FIG. 3, may also be provided. The description ofthe processes performed by the tank assemblies are examples. Variousother immersion processes may also of course be performed using theprocess system 20.

Referring still to FIG. 3, an immersion robot 106 is centrallypositioned between the tank assemblies 100, 102, 104 and 105. As shownin FIGS. 3 and 8, the immersion robot 106 includes an arm 110 attachedto a rotation/elevation post 108. An end effector 112 is attached to thearm, and is adapted to carry wafers 11 5, directly, or optionally in atray or carrier. The arm 110 optionally includes an end effector releasejoint 118, so that the robot 106 can place an end effector 112 carryinga batch of wafers 115 into one of the tanks assemblies, detach from theend effector 112, and move to a different position to pick up andrelocate another batch of wafers, on another end effector 112.

Referring to FIG. 3, the rectangular tank assemblies 100, 102 and 104(as well as 105 if used) are generally located in an offset radialpattern. The tank centers 125 are offset from each other. The tankassemblies 100, 102, 104 and optionally 105, are nested, so that the endof one tank assembly is facing or alongside the side of an adjacent tankassembly. In addition, the short side of one tank is approximatelyparallel and coplaner with the long side of an adjacent tank assembly.This design allows the tank assemblies to fit within a small space,providing for a compact immersion module design, which minimizes theclean room floor space required for the immersion module.

Referring now to FIGS. 12 and 14, the first tank assembly 100, which ispreferably a chemical solution immersion tank assembly, has an exhaustplenum 130, which is positioned above the deck 80. A tank base 136surrounds the upper section of the tank 134, and helps to support thetank 134 on the deck 80. The lower end of the tank 134 extends below thedeck 80 into the utility space 77. A diffuser plate 132 is located nearthe bottom of the tank 134, to diffuse liquids provided to the tank.

The first tank assembly 100 includes an inlet 138 for supplying fluidinto the tank 134, below the diffuser plate 132. A drain 140 on the tank134 connects to a drain line. A tank lid 142 is pivotally attached tothe exhaust plenum by a lid hinge block 146. A lid actuator 144, whichmay be electrically or pneumatically driven, is attached to an actuatorblock 148 on the tank base 136, and to the lid 142, such that the lid142 can be pivoted open and closed with actuation of the lid actuator144.

Ridges 150 are provided around the top edges of the inner tank 156, toachieve desired flow characteristics. An overflow channel 158 surroundsthe upper edge of the inner tank 156, to collect fluid running over theridges 150, and channeling the collected overflow fluid to an overflowdrain 154. Vents 152 are provided along the inside surfaces of theexhaust plenum, to reduce escape of vapors into the immersion chamber75.

FIG. 13 shows a quick dump rinse tank assembly as a second tank assembly102. Referring to FIG. 13, the quick dump rinse tank assembly (QDR) hasan exhaust plenum 130, a tank base 136, a tank lid 142, actuator 144,actuator block 148, a hinge lid block 146, a diffuser plate 132, etc. asdescribed above with reference to the tank assembly 100 shown in FIG.12. The tank assembly 102 also has a pair of spray bars 172 along thelonger sides of the rectangular exhaust plenum 130. Fluid inlets 176extend through the exhaust plenum 130, to provide fluid to the spraybars 172. A tank 180 in the tank assembly 102 has a large drain opening181 controlled by a valve 183. The drain opening 181 extends into a dumpreservoir 184, and is surrounded by a shroud 182.

In use, the various movements of robots, actuators, doors, and thecontrol of pumps, heaters, valves, etc. are controlled by the controller44, or by a separate controller located apart from the process system20. The process robot 90, in a typical application, withdraws a batch ofwafers 115 from a process chamber 28 in the process module, and moveslaterally on the rail 66, until the wafers are in alignment with theopening 79 in the front panel 78 of the immersion module 24. Theimmersion robot 106 is controlled to move the end effector 118, to aposition adjacent the opening or window 79, as shown in FIG. 3. Theprocess robot 60 then moves down, off loading the wafers 115 onto theend effector 1 18. The process robot 60 then typically moves to performother functions within the system 20. The post 108 of the immersionrobot 106 turns (180°) so that the end effector 118 carrying the wafers11 5 is aligned over the first tank assembly 100. The lid actuator 144is controlled to open the lid 142, immediately before the end effector118 arrives over the first tank 100. The robot 106 then lowers the endeffector holding the wafers into the tank 134. Process fluid is eitheralready present in the tank 134, or is provided into the tank after thewafers 115 are moved into the tank. The wafers 115 undergo an immersionprocess within the tank 134, using known methods.

As shown in FIG. 12, the exhaust plenum 130 has a cutout 153. Thisallows the arm 110 to move down to a position flush or below the topsurface of the exhaust plenum 130. The tank lid 142 is then closed, viacontrol of the lid actuator 144. Processing with the lid 142 closedreduces release of vapors from the tank assembly 100.

When immersion processing in the first tank assembly 134 is completed,the lid 142 is opened, and the immersion robot 106 lifts the wafers 115out of the tank assembly 100. The robot 106 then pivots (e.g., 90°) sothat the wafers 115 are positioned over the second tank assembly 102.

Referring to FIGS. 8 and 13, the lid 142 of the tank assembly 102 isopened and the robot lowers the wafers into the tank 180. As the wafers115 are lowered into the tank 180 of the tank assembly 102, they areoptionally sprayed, typically with a rinsing fluid, such as de-ionizedwater, via the spray nozzles 174. After the wafers are lowered entirelyinto the tank 180, the lid 142 is closed. The wafers 115 are rinsed by arinsing fluid within the tank 180. At an appropriate time, the valve 183is rapidly opened, quickly dumping or draining the rinsing fluid out ofthe tank 180, and into the dump reservoir 184. The drain 181 is largerelative to the tank volume, so that the tank can be quickly drained.For example, in the embodiment shown, the drain 181 has an insidediameter of from 90-160 mm, preferably about 125 mm, and the volume ofthe tank 180 ranges from 20-40 liters, and preferably about 30 liters.

After the tank 180 is drained, the lid 142 of the tank assembly 102 isopened, and the robot 106 lifts the wafers 115 up and out of the tank180, pivots 90° (counterclockwise in FIG. 3) to position the wafers 115over the next or third tank 104, typically a dryer, such as a surfacetension effect dryer. The lid 142 on the dryer or third tank is opened,and the robot moves the wafers into the third tank, for e.g., drying.After drying, the robot 106 lifts the wafers 115 out of the third tank,an moves them back to the position adjacent to the opening 79. Theprocess robot 60 then returns to the immersion module, picks up thewafers from the process robot 60, and carries the wafers to the stocker,where they may be temporarily stored while waiting for removal from thesystem 20.

Referring to FIG. 4, air flow through the immersion module 24 iscontrolled to reduce contamination of the wafers 11 5 and to controlvapors. As indicated by the arrows A in FIG. 4, air flows downwardlythrough the immersion chamber 75. Air flows downwardly over the tanks,outwardly towards the walls surrounding the immersion chamber 75,downwardly through down flow vents 88, located along the perimeter ofthe deck 80, and then into the utility space 77 below the deck 80. Airis then drawn out of the utility area 77 (via a facility vacuum source).This air flow tends to exhaust vapors which may be released from thetanks into the immersion chamber 75.

Air vents 152 in the exhaust plenum 130 also draw vapors from thesurface of the liquid in the inner tank 156, with the vapors moveddownwardly into the utility space 77 and out of the system 20.

Air flow within the system 20 is configured so that air is constantlyflowing into the immersion chamber 75, and exhausting downwardly out ofthe immersion chamber 75 into the utility space 77 or to a facility airexhaust. This air flow confines vapors to the immersion chamber 75, andalso evacuates vapors from the immersion chamber 75, to reduce risk ofcontamination of the wafers 115.

The window or opening 75 in the front panel 78 through which the processrobot 60 moves to deliver or remove wafers 115 to the immersion robot106 is minimized, to close off the immersion chamber 75 from the rest ofthe system 20, yet while still allowing robot access. Air flow iscontrolled so that air flows inwardly into the immersion chamber 75through the opening 79.

The deck 80 is inclined slightly forward so that any liquid collectingon the deck 80 will run down hill to a collection drain at the front ofthe deck 80. The floor panel 86 is similarly inclined so that anyliquids collecting on the floor panel will run to a floor panel drain.

Mega sonic transducers 160 may optionally be included in the tankassemblies.

Thus, a novel process system, a novel immersion module, and novel tankassemblies and methods have been shown and described. Variousmodifications may of course be made without departing from the spiritand scope of the invention. The invention, therefore, should not berestricted except to the following claims, and their equivalents.

What is claimed is:
 1. A process system for immersion processing wafers,comprising: a stocker module having positions for storing wafers to beprocessed; a process module having at least one process chamber; animmersion module adjacent to and detached from the process module toavoid transmission of vibration from the process module to the immersionmodule; and a process robot movable between the stocker module, theprocess module and the immersion module, for carrying wafers to and fromthe modules.
 2. The process system of claim 1 where the immersion moduleis between the process module and the stocker module.
 3. The module ofclaim 2 further comprising a lip exhaust in the first tank.
 4. Thesystem of claim 1 further including an airflow system connected to theimmersion module to control flow of vapors within the immersion module.5. The system of claim 1 further including a track extending in front ofthe stocker, process and immersion modules, with the process robotmoveable linearly along the track.
 6. The system of claim 1 with theimmersion module comprising: a first immersion tank; a second immersiontank; with the first and second immersion tanks located in an offsetradial orientation; and an immersion module robot positioned for movingfrom the first tank to the second tank.
 7. The system of claim 6 wherethe tanks are rectangular and have a pair of long sides attached to apair of short sides, and with a short side of the first tank paralleland coplaner with a long side of the second tank.
 8. The system of claim6 further comprising a lid on each of the tanks.
 9. The system of claim6 with the immersion module further comprising: a third immersion tank;with the first tank radially offset from the second tank, and with thesecond tank radially offset from the third tank; and with with theimmersion module robot having a base located between the first, secondand third tanks.
 10. The system of claim 9 where the robot is locatedcentrally between the tanks.
 11. The system of claim 1 further includinga plurality of tanks in the immersion module and an immersion modulerobot positioned within the immersion module for moving wafers betweentanks in the immersion module.
 12. The system of claim 11 where theimmersion module robot includes an end effector adapted to hold wafers,and with the end effector detachable from the immersion module robot, sothat the immersion module robot can place the end effector carrying afirst batch of wafers into a first tank within the immersion module, andthen move to perform another function within the immersion module, whilethe first batch of wafers remains immersed in the first tank.
 13. Thesystem of claim 11 with at least one of the immersion tank including aquick dump means for rapidly releasing liquid from the tank.
 14. Aprocess system for immersion processing wafers, comprising: a stockermodule having positions for storing wafers to be processed; a processmodule; an immersion module adjacent to and detached from the processmodule and the stocker module to avoid transmission of vibration fromthe process module to the immersion module; a track extending along thestocker, process and immersion modules; and a process robot movable onthe track between the stocker module, the process module and theimmersion module, for carrying wafers to aid from the modules.
 15. Thesystem of claim 14 with the track not contacting the immersion module.